Adding a Laundry Sink to Existing Washer Drain

[bradleonard]

I posted this question at the end of a very old thread (http://www.terrylove.com/forums/show...ht=#post277172) and didn't receive a response, I have an existing standpipe for my washing machine going into a 2" drain vented above with 2". The washing machine drain comes from the left in my picture.



I would like to add a laundry sink to this drain. My question is Washington Code specific as I live in Washington. Can I simply add a cross T where the washing machine enters this stack and drain both the sink and washer at the same height, or do I need to do a vent in the horizontal line come from the sink trap just as you have shown in the picture at the beginning of this thread?

[Terry]

You can use a fixture cross at the same height and use the one vent.

Not a san cross. What you have now is a SanTee.
A double santee wouldn't work. I would need a double fixture fitting.

[hj]

Offhand, from the pictures, I would suspect that a fixture fitting would make the drain go in the wrong direction and create a convoluted drain if the sink is going along the back, concrete, wall.

[bradleonard]

So I went to Home Depot and found these two fittings. It appears to me that I need a double fixture fitting, shown on the left. Is this correct? if I replace the T that I have right now with a double fixture fitting I won't need to change the vent at all?

[Terry]

Yes, the box on the left. If you need to get closer to the wall, you can offset below the fixture tee.

[shacko]

Yes, the box on the left. If you need to get closer to the wall, you can offset below the fixture tee.

Hey Terry, that looks like a double combine, not a double fixture fitting?